The sport of mountain biking as it is generally known has become extremely popular with a broad range of bicycle enthusiasts. While a variety of events have evolved which form various facets of the sport of mountain biking, basically mountain biking differs from other bicycle and cycling activities in its application to rough terrain, hilly terrain, and difficult trails or paths through wooded areas or the like. The sport is physically challenging for the enthusiast and provides increased simulation for the mountain biker due to the constantly varying circumstances presented to the mountain biker. In addition to providing physical beneficial exercise and sport or recreation activities, various facets of mountain biking have become extremely competitive often in an organized amateur or professional format.
Not surprisingly, the typical bicycle utilized in mountain biking (usually called a mountain bike) differs from standard cycles used in pleasure riding or road racing activities. Several different aspects are most noticeable in distinguishing mountain bikes from other cycles. For example, the frame is substantially stronger and more rigid and is due to weight considerations often fabricated of relatively exotic metals and materials. Further, the typical mountain bike utilizes wider tires having more aggressive treads and provides derailleur systems which provide substantially more gear ratios to meet the anticipated hilly terrain of the mountain biker. In addition, the front wheel and often the rear wheel as well are supported by energy absorbing dampened suspension systems.
Such mountain bikes suspension systems are subject to the same operational criteria as has been encountered in other vehicle suspension systems such as motorcycles and automobiles in a general sense. That is to say, the various characteristics by which a suspension system is described include the comfort provided, the energy absorbing capability, control maintenance, as well as steering and general "feel". In addition, mountain bikes encounter an additional characteristic in that the attitude or inclination of the bike must be carefully controlled. These various qualities of suspension systems are often at odds or conflicting. For example, the degree of energy absorption and the maintenance of control are often conflicting requirements. Similarly, the ability to absorb energy within the system and the maintenance of bike attitude or inclination also conflict. By further example, the quality of comfort often conflicts with the qualities of road feel and control maintenance.
Of particular interest to the present invention is the front suspension system for such mountain bikes. In attempting to meet these various needs, practitioners in the art have in general arrived at various levels and combinations of compromises between suspension qualities. The most typical front suspension structure employs a pair of dampened spring struts which support front wheel axle and extend upwardly to be secured to a pivoting strut support pivotally coupled to the head tube of the bicycle frame.
FIG. 1 sets forth a rear view of a typical front fork and suspension assembly for a prior art mountain bike generally referenced by numeral 10. For purposes of illustration, FIG. 1 omits various apparatus such as the brake assembly or the like to avoid unduly cluttering the figure. Thus, in accordance with conventional fabrication techniques, front fork and suspension assembly 10 includes a horizontally extending strut support 13 having a cup assembly 12 pivotally coupling strut support 13 to a head tube 11. The latter is secured to and forms a part of the bicycle frame. Strut support 13 includes attachments 16 and 17 at each end thereof and defines a generally inverted U-shape member. A pair of suspension struts 14 and 15 are secured at their upper ends to strut support 13 by attachments 16 and 17 respectively and extend downwardly to receive the front axle of a front wheel 18 (not shown). Front wheel 18 is, as a result, spring supported by dampened struts 14 and 15. FIG. 1 depicts the typical "normal" riding position for front fork and suspension system 10 and the corresponding position of front wheel 18 relative thereto. As front wheel 18 encounters various bumps and obstacles tending to raise the bike, front wheel 18 is driven upwardly causing struts 14 and 15 to compress initially in an energy absorbing action which is dampened by the struts. The distance available for front wheel 18 to move upwardly as struts 14 and 15 compress is shown as suspension travel limit distance 19. Due to the strength required for attachments 16 and 17 to struts 14 and 15 of a mountain bike, strut support 13 is necessarily fabricated of a high strength relatively thick member. This in turn substantially limits the available suspension travel distance for front wheel 18.
The travel distance available for a bicycle front suspension forms a basic limitation on the capability of the suspension system to properly perform. In addition, the operation and characteristics of the dampened struts form an additional defining characteristic for the front suspension system. In addition, the overall strength and rigidity provided by the front wheel suspension system of a mountain bike further limits the performance capability of the bike.
While the prior art mountain bike suspension systems have performed adequately under many operating conditions, there remains nonetheless a continuing need in the art for evermore improved lightweight and high strength mountain bike front suspension systems.